1. Introduction to Biology

2. Chemistry

3. Water

4. Biomolecules

5. Cell Components

6. The Membrane

7. Energy and Metabolism

8. Respiration

9. Photosynthesis

10. Cell Signaling

11. Cell Division

12. Meiosis

13. Mendelian Genetics

14. DNA Synthesis

15. Gene Expression

16. Regulation of Expression

17. Viruses

18. Biotechnology

19. Genomics

20. Development

21. Evolution by Natural Selection

22. Evolution of Populations

23. Speciation

24. History of Life on Earth

25. Phylogeny

26. Prokaryotes

27. Protists

28. Plants

29. Fungi

30. Overview of Animals

31. Invertebrates

32. Vertebrates

33. Plant Anatomy

34. Vascular Plant Transport

35. Soil

36. Plant Reproduction

37. Plant Sensation and Response

38. Animal Form and Function

39. Digestive System

40. Circulatory System

41. Immune System

42. Osmoregulation and Excretion

43. Endocrine System

44. Animal Reproduction

45. Nervous System

46. Sensory Systems

47. Muscle Systems

48. Ecology

49. Animal Behavior

50. Population Ecology

51. Community Ecology

52. Ecosystems

53. Conservation Biology

[BOOK BIO] CLUTCH

No. Root pressure is upward pressure generated by the accumulation of water in the stele.

No. Adhesion is the sticking together of two substances.

No. This is the process by which light energy is converted to chemical energy stored in the bonds of organic compounds.

No. Pressure flow can be responsible for the movement of water but not for a change in the state of water.

The answer is related to evaporation.

One of your friends has a terrarium on her windowsill containing various houseplants. She wonders why the glass is often fogged with water droplets. What would you tell her is the cause of the droplets?

No. It is true that water molecules can cross a plasma membrane due to simple diffusion, but there must be other methods to account for the amount of water that can flow into a plant cell in a given time.

No. It is true that some transport proteins facilitate diffusion of water, but this is not the best answer.

No. Aquaporins are transport proteins that facilitate the diffusion of water, but this is not the best answer.

None of the specific responses listed is correct.

No. At least one of the listed responses is correct.

All of the specific responses listed are correct.

Recent discoveries have elucidated how water can cross membranes as rapidly as it does.

Why does rapid movement of water molecules across the plasma membrane of a plant cell occur?

No. Solute potential is always less than 0.

No. In a turgid cell, pressure potential must be positive.

No. In a turgid cell, water potential = 0.

Turgid means firm. What conditions would make a plant cell turgid?

In a turgid cell, __________.

transport water and minerals from shoots to roots

No. The direction of transport in the xylem is just the opposite.

increase root surface area for water and mineral absorption

No. Xylem transports water from the roots to the shoots after absorption has already occurred.

transport water and minerals from roots to shoots

What drives bulk flow in the xylem?

The purpose of the xylem is to __________.

Xylem and Phloem - Part 3 - Translocation - Transport in Plants | Plants | Biology | FuseSchool

A mutant plant lacking the ability to pump protons out of leaf companion cells will be unable to do which of the following?
a. initiate transpiration
b. load sucrose into sieve-tube elements
c. carry out photosynthesis
d. transport water through the xylem

Root Pressure : Transportation | Biology | Science |  Class 10

Cohesion, Adhesion, & Surface Tension

No. The epidermis, the outermost layer of a root, is permeable to water.

No. The pericycle gives rise to lateral roots.

Consider the role of the Casparian strip.

In a plant root, the one structure that water cannot move past via the apoplast is the __________.

Transpiration is fastest when humidity is low and temperature is high, but in some plants it seems to increase in response to light as well. During one 12-hour period when cloud cover and light intensity varied frequently, a scientist studying a certain crop plant recorded the data in the table (top right). (The transpiration rates are grams of water per square meter of leaf area per hour.) Do these data support the hypothesis that the plants transpire more when the light is more intense? If so, is the effect independent of temperature and humidity? Explain your answer. (Hint: Look for overall trends in each column, and then compare pairs of data within each column and between columns.) <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/c8a3c283a3f0cb70-1677808877365.jpg" style="width: 300px;">

No. Water potential = pressure potential + solute potential.

Apply the equation for water potential.

A cell has a pressure potential of 0 and a solute potential of -0.7 MPa. What is its water potential?

Week 2  1 Water potential  How water moves in plants

Salt is used to melt snow and keep roads clear during the winter in many cities. Land adjacent to de-iced roads often ends up with a high concentration of salt in the soil. Explain why plants growing near salted roads may appear wilted in the spring.

Animation: Transport of Xylem Sap

THE UPTAKE AND TRANSPORT OF WATER AND MINERAL IONS BY ROOT SYSTEM

No. Mesophyll cells are specialized for photosynthesis.

No. Guard cells regulate the opening of stomata.

No. Bundle sheaths are protective structures that enclose veins.

No. Aquaporin is a protein that facilitates osmosis.

Which cells are modified to enhance solute transfer?

Cells that are specialized for the transport of sugar between apoplast and symplast are __________ cells.

blue light triggering the efflux of K+ from guard cells

No. An efflux of K+ would lead to a loss of water from guard cells and the closing of stomata.

No. Stomatal closure can be the result of excessively high temperatures.

No. It is decreased CO2 levels that cause stomata to open.

No. Abscisic acid, produced in response to water loss, triggers the closing of stomata.

blue light triggering the uptake of K+ by guard cells

What mechanisms can cause guard cells to become more turgid?

Stomata open during the day in response to __________.

Turgor Pressure

Agriculture is by far the biggest user of water in arid western states, including Colorado, Arizona, and California. The populations of these states are growing, and there is an ongoing conflict between cities and farm regions over water. To ensure water supplies for urban growth, cities are purchasing water rights from farmers. This is often the least expensive way for a city to obtain more water, and some farmers can make more money selling water than growing crops. Discuss the possible consequences of this trend. Is this the best way to allocate water for all concerned? Why or why not?

Atmospheric CO2 has been increasing rapidly since the late 1800s, largely due to human activities. Recall that CO2 enters leaves through stomata and can then be used for photosynthesis. However, transpiration occurs as a result of water evaporating through stomata. How have plants responded to elevated CO2 levels? 

The amount of water that evaporates from stomata over a period of time is referred to as stomatal conductance, which is determined largely by the number of stomata in a given area of leaf surface. Researchers obtained specimens from preserved collections and measured stomatal conductance in leaves from oak trees and pine trees that grew at various times under different CO2 levels. The data are shown in the following graph. In general, is the maximum stomatal conductance rate in plants more or less than it was a century ago? <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/80661c7d8d1de3a0-1677306973520.jpg" style="width: 300px;">

What important role does the Casparian strip play in the movement of water through plants?
a. forces water to move through the cytoplasm of living endodermal cells as it makes its way from the soil to the xylem
b. causes cells to shrink, thereby increasing pressure within cells
c. loads sugars into xylem, thereby causing water to enter the xylem by osmosis
d. acts as a filter that prevents salts, heavy metals, and other pollutants from entering root hairs

No. The plasmodesmata are part of the symplast; they are cytoplasmic connections through adjacent plant cell walls.

No. The symplast is the cytoplasmic connection between adjacent plant cells.

No. The Casparian strip is a structure that bars the passage of minerals into the vascular cylinder.

Review the major compartments of plant tissues.

The continuum of cell walls connecting neighboring cells is defined as the __________.

Water potential

Plant Structure and Adaptations

Compared with a cell with few aquaporin proteins in its membrane, a cell containing many aquaporin proteins will
a. have a faster rate of osmosis.
b. have a lower water potential.
c. have a higher water potential.
d. accumulate water by active transport.

How Water Enters Xylem

Atmospheric CO2 has been increasing rapidly since the late 1800s, largely due to human activities. Recall that CO2 enters leaves through stomata and can then be used for photosynthesis. However, transpiration occurs as a result of water evaporating through stomata. How have plants responded to elevated CO2 levels?

What impact, if any, do you predict elevated CO2 levels will have on the number of stomata in leaves, and on the transpiration rate?

What would enhance water uptake by a plant cell?
a. decreasing the Ψ of the surrounding solution
b. positive pressure on the surrounding solution
c. the loss of solutes from the cell
d. increasing the Ψ of the cytoplasm

Types of Plant Tissues

Xylem and Phloem - Transport in Plants | Biology | FreeAnimatedEducation

No. Transpiration, the evaporation of water from stomata, pulls fluid up the xylem.

the high water potential of the vascular cylinder relative to the root cortex

No. Due to an accumulation of minerals, the vascular cylinder has a lower water potential than the root cortex.

the pumping of minerals out of the vascular cylinder

No. Pumping minerals out of the vascular cylinder would result in the movement of water from the vascular cylinder to the root cortex.

the accumulation of minerals in the vascular cylinder

What kind of water potential would create pressure in the roots?

Root pressure is attributable to __________.

No. Xylem cells contract when the fluid within is under tension. It is an effect, not a cause.

No. Transpiration, not root pressure, is the major force moving xylem sap upward.

Breakdown and release of energy of sugar molecules

No. Transpiration does not require the plant to expend energy.

Osmotic changes caused by alterations in salt content

No. The transport of water is dependent on relative water potentials as well as the cohesion and adhesion of water.

This is a process that culminates at the surface of a leaf.

What is the ultimate source of energy that moves water upward in the trunk of a tree?

the xylem's ability to transport minerals from roots to shoots

No. Viruses use the phloem to spread throughout the plant.

the ability of phloem to transmit electrical signals

No. Viruses do not exploit pathways that transmit electrical signals.

No. The Casparian strip would tend to keep viruses from entering the plant.

the ability of plasmodesmata to dilate to allow large particles to move between cells

What system has access to the insides of the most cells?

In order to be transported throughout a plant, viruses exploit __________.

Consider the following statements regarding the transport of phloem sap. Select True or False for each statement.
T/F This is a passive process that is driven by the evaporation of water from leaves.
T/F Sugars tend to move from sources to sinks.
T/F Phloem sap moves through sieve-tube elements under positive pressure.
T/F Sieve-tube elements and vessel elements are commonly involved in the transport of phloem sap.

The cells of a certain plant species can accumulate solutes to create very low solute potentials. Which of these statements is correct?
a. The plant's transpiration rates will tend to be extremely low.
b. The plant can compete for water effectively and live in
c. relatively dry soils.
d. The plant will grow most effectively in soils that are saturated with water year-round.
e. The plant's leaves will wilt easily.

Cohesion-Tension Theory

No. Only certain prokaryotes are capable of nitrogen fixation.

unable to transport water or solutes to the leaves

No. The Casparian strip is a barrier to the flow of water and solutes.

able to exert greater root pressure than normal plants

No. Without the Casparian strip, water would be able to flow back out of the stele to the root cortex.

No. The lack of a Casparian strip would not decrease the availability of water to a plant.

unable to control the amounts of water and solutes it absorbs

Consider the location and function of the Casparian strip.

A botanist discovered a mutant plant that is unable to produce the material that forms the Casparian strip. This plant is __________.

Animation:  Phloem Transport 

No. Though root pressure plays a role, it is effective over only a few meters. Even in small plants, transpirational pull plays a greater role.

No. The water pressure in leaves is less than atmospheric pressure.

The Casparian strip blocking water molecules from moving out

No. Though this has an effect on root pressure, transpirational pull plays a greater role.

No. This type of movement concerns the flow of phloem sap and not the flow of water in xylem.

Consider the nature of water.

What keeps the force of gravity from overcoming transpirational pull?

Fill in the blanks in this concept map to help you tie together key concepts concerning transport in plants. <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/efef57991bbd4804-1677808830966.jpg" style="width: 300px;">

No. Guard cells are not involved in bulk flow.

Tracheids, plasmodesmata, and sieve tubes

No. Plasmodesmata are not involved with bulk flow.

Consider which groups are xylem and phloem cells.

Which of the cells below are involved with bulk flow?

Researchers compared the amino acid sequences of the transport protein in zebrafish, puffer fish, mice, and humans. They found many stretches with identical sequences in all four species. Does this mean that the corresponding mRNA base sequences are also the same in these four species? Explain why or why not.

Intro to vascular tissues (xylem & phloem) | Life processes | Biology | Khan Academy

&Psi;S may be either positive or negative.

No. The maximum possible &Psi;S is that found in pure water, and it is defined as 0. The &Psi;S of any solution is less than 0.

&Psi;S is always greater than &Psi;P.

No. &Psi;S must be less than 0; &Psi;P may be positive.

No. &Psi;P may be positive or negative.

No. &Psi;S is always less than 0, and &Psi;P may be positive or negative.

&Psi;P may be either positive or negative.

Think about what S and P symbolize in this equation.

The water potential of a cell is defined by the equation &Psi; = &Psi;S + &Psi;P. Which of the following statements is true?

Water Potential

No. Positive pressure in the xylem is caused by root pressure and is only effective over short distances.

Positive pressure potential in the mesophyll

No. Positive pressure in the mesophyll can only occur if there is no transpiration, the driving force for water transport in the xylem.

Negative pressure potential in the guard cells

No. Negative pressure in living plant cells results in plasmolysis. Guard cells open the stoma when under positive pressure.

Phloem transport being in the opposite direction from the xylem transport

No. Transport in the xylem is independent of phloem transport.

Negative pressure potential in the leaf mesophyll

What drives the flow of xylem in a tree?

Which of the following conditions will result in the fastest transport through the xylem in a tree, assuming adequate water supply in the roots?

Movement of water into the Root

No. The apoplast is the continuum of cell walls.